channel_folders: Check max length restrictions while updating.

This commit updates code to make sure we check maximum allowed
length for name and description for channel folders when updating
them.

zerver/openapi/zulip.yaml

@@ -24465,11 +24465,19 @@ paths:
                 name:
                   description: |
                     The new name of the channel folder.
+
+                    Clients should use the `max_channel_folder_name_length` returned
+                    by the [`POST /register`](/api/register-queue) endpoint to determine
+                    the maximum channel folder name length.
                   type: string
                   example: backend
                 description:
                   description: |
                     The new description of the channel folder.
+
+                    Clients should use the `max_channel_folder_description_length`
+                    returned by the [`POST /register`](/api/register-queue) endpoint
+                    to determine the maximum channel folder description length.
                   type: string
                   example: Backend channels.
                 is_archived:

zerver/tests/test_channel_folders.py

@@ -238,6 +238,13 @@ class UpdateChannelFoldersTest(ZulipTestCase):
         result = self.client_patch(f"/json/channel_folders/{channel_folder_id}", params)
         self.assert_json_error(result, "Invalid character in channel folder name, at position 4.")
 
+        long_name = "a" * (ChannelFolder.MAX_NAME_LENGTH + 1)
+        params = {"name": long_name}
+        result = self.client_patch(f"/json/channel_folders/{channel_folder_id}", params)
+        self.assert_json_error(
+            result, f"name is too long (limit: {ChannelFolder.MAX_NAME_LENGTH} characters)"
+        )
+
     def test_updating_channel_folder_description(self) -> None:
         channel_folder = check_add_channel_folder(
             get_realm("zulip"),
@@ -276,6 +283,13 @@ class UpdateChannelFoldersTest(ZulipTestCase):
         self.assertEqual(channel_folder.description, "")
         self.assertEqual(channel_folder.rendered_description, "")
 
+        params = {"description": "a" * (ChannelFolder.MAX_DESCRIPTION_LENGTH + 1)}
+        result = self.client_patch(f"/json/channel_folders/{channel_folder_id}", params)
+        self.assert_json_error(
+            result,
+            f"description is too long (limit: {ChannelFolder.MAX_DESCRIPTION_LENGTH} characters)",
+        )
+
     def test_archiving_and_unarchiving_channel_folder(self) -> None:
         desdemona = self.example_user("desdemona")
         realm = get_realm("zulip")

zerver/views/channel_folders.py

@@ -59,9 +59,11 @@ def update_channel_folder(
     user_profile: UserProfile,
     *,
     channel_folder_id: PathOnly[int],
-    description: str | None = None,
+    description: Annotated[
+        str | None, StringConstraints(max_length=ChannelFolder.MAX_DESCRIPTION_LENGTH)
+    ] = None,
     is_archived: Json[bool] | None = None,
-    name: str | None = None,
+    name: Annotated[str | None, StringConstraints(max_length=ChannelFolder.MAX_NAME_LENGTH)] = None,
 ) -> HttpResponse:
     channel_folder = get_channel_folder_by_id(channel_folder_id, user_profile.realm)